body::before{
    background-image: url(../image/hui.png);
}

#screen {

    width: 450px;
    height: 50px;
    margin-top: 10px;
    background-color: #fff;
    font-size: 22px;
    line-height: 50px;
    text-align: center;
}

#backButton{
    width: 450px;
    height: 50px;
    margin-top: 10px;
    background-color: orange;
    font-size: 22px;
    line-height: 50px;
    text-align: center;
    border: none;
    outline: none;
    border-radius: 10px;
    color: white; /* 添加这一行，设置字体颜色为白色 */
}


#backButton:active #exit-login:active{
    background-color: gray;
}
